Issue Highlights

Abstract

HomeCirculationVol. 114, No. 10Issue Highlights Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIssue Highlights Originally published5 Sep 2006https://doi.org/10.1161/circ.114.10.985Circulation. 2006;114:985WILD-TYPE AND MUTANT HCN CHANNELS IN A TANDEM BIOLOGICAL-ELECTRONIC CARDIAC PACEMAKER, by Bucchi et al.andBIOARTIFICIAL SINUS NODE CONSTRUCTED VIA IN VIVO GENE TRANSFER OF AN ENGINEERED PACEMAKER HCN CHANNEL REDUCES THE DEPENDENCE ON ELECTRONIC PACEMAKER IN A SICK-SINUS SYNDROME MODEL, by Tse et al.Advances in technology have improved reliability of pacemaker therapy for bradycardia due to sinus node dysfunction or complete atrioventricular block. However, these electronic devices remain imperfect and have finite battery longevity. Recent manufacturers’ advisories and US Food and Drug Administration recalls due to component failures highlight the need for continued improvement. In this issue of Circulation, 2 separate studies by Bucchi and colleagues and by Tse and colleagues report their findings of experiments using bioengineered pacemaker channel technology. Both groups found a decrease in electronic pacing when constructs with engineered modified HCN channels were transfected into cardiac tissue. Bucchi and colleagues demonstrated that a mutant biological pacemaker implanted in a canine atrioventricular block model conferred catecholamine-sensitive rate improvement and less reliance on electronic pacemaker. Tse and colleagues overexpressed a different mutant HCN channel in a porcine sinus node dysfunction model, and similarly showed that transduction in the atria induced spontaneous automaticity and a catecholamine-responsive physiological heart rate that reduced electronic pacing. Although not yet ready to render pacemakers obsolete, these studies further our understanding of cardiac impulse generation and conduction. These hybrid electronic-biological pacemaker systems illustrate important advances in gene therapy for electrophysiological abnormalities. See p 992 and p 1000 (editorial on p 986).SPECIFIC TEMPORAL PROFILE OF MATRIX METALLOPROTEINASE RELEASE OCCURS IN PATIENTS AFTER MYOCARDIAL INFARCTION: RELATION TO LEFT VENTRICULAR REMODELING, by Webb et al.Experimental studies in animals have shown that matrix metalloproteinases (MMPs) and their endogenous inhibitors, the tissue inhibitors of MMPs (TIMPs), play an important role in regulating myocardial remodeling after myocardial infarction (MI). Webb et al measured plasma levels of MMP-8 and -9 and TIMP-1, -2, and -4 sequentially over the first 180 days after MI to characterize the temporal pattern of MMP and TIMP in this clinical setting. A specific MMP/TIMP temporal profile was found, with early increases in MMP-8 and -9 and a later decrease in TIMP-4. These findings raise the possibility that the MMP/TIMP profile can be used as a biomarker and may yield diagnostic and prognostic information in the post-MI period. See p 1020.DISTRIBUTION OF LIPOPROTEINS BY AGE AND GENDER IN ADOLESCENTS, by Jolliffe and JanssenAtherosclerosis can begin at a young age, and the rate of progression is related to plasma lipoprotein concentrations. Lipoprotein concentrations tend to persist from youth into adulthood, providing further evidence that it is imperative to identify and manage high-risk lipoprotein concentrations at an early age. The current pediatric National Cholesterol Education Program (NCEP) classification system does not recognize that lipoprotein concentrations fluctuate naturally with growth and maturation. Jolliffe and Janssen have devised an age-specific lipoprotein classification system for adolescents. The adolescent thresholds, which were developed using nationally representative data sets, were anchored to the adult NCEP thresholds using growth curve modeling. These adolescent lipoprotein classification systems are presented in a series of growth curves and tables that are practical for both clinical and research settings. It is hoped that the classification systems developed in this study will better identify adolescents with high-risk lipoprotein concentrations; validation studies are needed, however. See p 1056.Visit http://circ.ahajournals.org:Images in Cardiovascular MedicineScimitar Syndrome: Complete Diagnosis by Transthoracic Echocardiography. See p e373. Download figureDownload PowerPointMyocardial Fibroma in Gorlin Syndrome by Cardiac Magnetic Resonance Imaging. See p e376.Large Pulmonary Artery Aneurysm Rupture in Hughes-Stovin Syndrome: Multidetector Computed Tomography Pattern and Endovascular Treatment. See p e380.Book ReviewManual of Vascular Diseases. See p e382.CorrespondenceSee p e383. Previous Back to top Next FiguresReferencesRelatedDetails September 5, 2006Vol 114, Issue 10 Advertisement Article InformationMetrics https://doi.org/10.1161/circ.114.10.985 Originally publishedSeptember 5, 2006 PDF download Advertisement